Field of the Invention
The present invention relates to a technique of generating a depth map of a target object.
Description of the Related Art
Conventionally there is a technique for generating a range image (a depth map), which represents a distribution of distances between a particular viewpoint and an object that has a three-dimensional shape, by using a point cloud that configures the object. In Japanese Patent Laid-Open No. 2006-107093, cells (voxels or the like) that configure a three-dimensional object defined by volume data are projected onto a plurality of reference projection planes, and a depth map is generated at a particular viewpoint by using two or more reference projection planes.
In the case of generating a range image, in Japanese Patent Laid-Open No. 2006-107093, for each position on the target object, a corresponding pixel position on the range image is specified, and a distance value representing a distance to the position is assigned as a pixel value of the pixel position. By such a method, it is possible to assign distance values to pixel positions on the range image that respectively correspond to each position on the target object. However, “pixel positions on the range image that respectively correspond to each position on the target object” are not necessarily contiguous positions on the range image. In other words, in a method of generating a range image in the conventional technique, pixels on the range image to which a distance value cannot be assigned (defective pixels) occur.